Résultat de la recherche
Confirmation that Rickettsia helvetica sp. nov. Is a Distinct Species of the Spotted Fever Group of Rickettsiae
We propose the name Rickettsia helvetica sp. nov. for a rickettsial serotype of unknown pathogenicity isolated in 1979 in Switzerland from Ixodes ricinus ticks and designated the Swiss agent. The growth characteristics and the results of microimmunofluorescence serologic typing, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blotting (immunoblotting) with specific mice sera, and a polymerase chain reaction followed by restriction fragment length polymorphism analysis confirmed previously reported preliminary findings which suggested that this rickettsia, to which a name was given provisionally, does represent a new member of the spotted fever group of rickettsiae. The type strain is C3 (Reference Center for Rickettsioses, Marseille, France).
Erythma chronicum migrans a tickborne – a tickborne spirochetosis. Short communication
Aspects nouveaux du rôle de vecteur joué par Ixodes Ricinus L. en Suisse. Note préliminaire
The authors, after having recalled their recent work on Ixodes ricinus ecology, give the new results about the part played by this species in the transmission of different infectious agents in Switzerland. I. ricinus was already known to be the most important vector of the tick borne encephalitis virus, and of protozoans of the Babesia genus. In this article, we describe the existence in the hemolymphe of different I. ricinus populations, of a rickettsia species related to the RMST group (Rocky-Mountain Spotted Fever), of a trypanosome, which is close to T. theileri, and of an infectious larval form (L3) of Dipetalonema rugosicauda. An outline is suggested with the object of illustrating the functioning of a natural foci of tick encephalitis. The biological significance of the unusual presence of trypanosomes and of larval filariae in ticks is also discussed. The authors underline the fact that rickettsia, trypanosomes and filarial forms are observed for the first time in Swiss I. ricinus.
Présence d'une rickettsie du groupe “Spotted Fever” chez Amblyomma Variegatum de Côte d’Ivoire
Ixodes ricinus : vector of a hitherto undescribed spotted fever group agent in Switzerland
A tick/rickettsial survey in various parts of Switzerland revealed the presence of a new, hitherto undescribed spotted fever group rickettsia ("Swiss agent") in up to 11.7% of I ricinus collected off vegetation. Infection in ticks was found to be generalized with rickettsiae developing intracellularly and occasionally also intranuclearly. As a result of massive growth in ovarial tissues, including the germinative cells, the rate oftransovarial and filial infection was 100%.
The "Swiss agent" appears to be nonpathogenic for guinea pigs, domestic rabbits, and Swiss mice, but in male meadow voles (Microtus pennsylvanicus) it produces a microscopically detectable infection in the tunica vaginalis. The rickettsia grows well in tissue culture systems including chick embryo fibroblast, Vero, and vole tissue cells, when inoculated via yolk sac into 5-day-old hens' eggs, it kills 100% of the embryos after 5 to 7 days.
Antigenic relatedness of the "Swiss agent" to rickettsiae of the spotted fever group was indicated by indirect and direct fluorescent antibody staining. Preliminary serologic typing by microimmunofluorescence and by microagglutination indicated that the "Swiss agent" differs from all prototype strains of spotted fever group rickettsiae studied so far.
Isolation of a cultivable spirochete from Ixodes ricinus ticks of Switzerland
We have isolated in BSK medium a spirochete of Ixodes ricinus ticks. The ticks were collected from an area of Switzerland where erythema chronicum migrans, a tick-borne, penicillin-ameliorated inflammatory disorder, is endemic. The I. ricinus spirochete was very similar in its morphology, polyacrylamide-gel-electrophoresis profile, and antigenic determinants to a spirochete that was previously isolated from Ixodes dammini ticks of the United States.